In a sewing machine referred to as zig zag sewing machine for making one or more required stitching patterns on a cloth, at least one cam follower is provided for following the peripheral surface of a pattern cam so as to oscillate the stitching needle corresponding to the shape of the pattern cam. Such sewing machine is also provided with a pattern selecting mechanism for selecting a required pattern cam from various pattern cams.
In one conventional pattern selecting mechanism, a cam follower is adapted to be moved to a position of the required pattern cam by manual rotating operation of a dial. The conventional cam selecting mechanism of the type has disadvantages in that an operator of the sewing machine must operate the dial by applying a strong turning force. In addition, it takes long time to complete the cam selecting operation of the required cam.
For eliminating those deflects, U.S. Pat. No. 3,874,312 discloses electric cam selector mechanism having a plurality of cam selector units each of which comprises a solenoid and an arm member being rotated by said solenoid to contact a corresponding pattern cam. This cam selector mechanism has disadvantages in that a number of solenoids must be provided, which requires large space relative to a limited space of a sewing machine and also the cam selector mechanism becomes much more complicated as the number of pattern cams is increased.